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Diseases of the Respiratory System
- 1. Diseases Diseases of the of the RespiRatoR RespiRatoR y system y system
- 3. Major Determinants of Disease • Diseases of one lung compartment tend to affect the others • The lungs are open to the environment, exposing them to infectious agents, allergens, irritants, & carcinogens • Most lung disease is caused by inhalation of material; the most common exception is autoimmune lung disease • Lost pulmonary membrane is not recoverable • Smoking is a major cause of lung disease • The heart & lungs are a functional unit; lung disease usually affects the heart; & heart disease usually affects the lungs
- 4. UppeR RespiRatoRy UppeR RespiRatoRy infections infections • Allergic rhinitis – “hay fever” – nasal mucosal edema – nasal discharge – sneezing – allergic conjunctivitis • “Colds” – transmitted through respiratory droplets – clear nasal discharge – low grade fever – if nasal discharge becomes colorful, it is an indication of secondary bacterial infection • Acute pharyngitis – “sore throat” – usually viral – bacterial infections more serious – red, swollen tonsils
- 5. caRcinoma of the caRcinoma of the LaRynx LaRynx • Common • Mostly in male smokers over 40 • Alcohol abuse increases the risk • Presents with – hoarseness – pain – cough – dysphagia – hemoptysis
- 6. ateLectasis ateLectasis • Collapse of a lung or part of a lung • Resorption – bronchial obstruction – air below obstruction completely absorbed – obstructions are • mucous plug • asthma • bronchitis • tumors • Compression – pressure exerted from pleural space or upward pressure on diaphragm • Contraction – scars cause constriction & collapse – TB
- 7. asthma asthma • Chronic inflammatory disease of small bronchi & bronchioles • Triggered by inhaled irritants & classified by irritant • Allergic • Occupational • Exercise-induced • Infectious • Others – drug reactions – emotional stress – severe air pollution • Hyperplastic mucous glands in bronchi, hypertrophied smooth muscle, edema, & marked inflammation
- 8. chRonic obstRUctive chRonic obstRUctive pULmonaRy Disease (copD) pULmonaRy Disease (copD) • Related diseases • Chronic bronchial outflow obstruction • Overlapping features
- 10. emphysema emphysema • Destruction of alveolar walls, alveoli merge to form large air spaces • Loss of surface area affects diffusion • 90% of cases are smokers
- 11. chRonic bRonchitis chRonic bRonchitis • Chronic cough that produces sputum for 3 consecutive months 2 years in a row • Primary cause is cigarette smoking • Chronic inflammation of bronchi • Simple chronic bronchitis • Chronic asthmatic bronchitis • Hereditary • Shortness of breath • Wheezing & coughing • Weight loss • Barrel-chested
- 12. • Cigarette smoke irritates lung & causes inflammation • Inflammatory cells release digestive enzymes • These enzymes normally inhibited by alpha-1 antitrypsin • AAT inhibited by smoke & so enzymes digest lung tissue
- 13. Bronchiectasis Bronchiectasis • Marked, permanent dilation of small bronchi • Destruction of smooth muscle & elastic supporting tissue • Must have obstruction & infection – obstruction causes mucus retention – infection damages bronchial walls which causes excess mucus production • Not a primary condition • Typically involves lower lobes • Persistent cough
- 14. restrictive Lung restrictive Lung Disease Disease • Chronic inflammation making lungs stiff & inelastic • Affects diffusion • Scar tissue accumulates in the interstitium • Mostly cause is unknown • Equal decline in FEV1 & FVC • Usually presents with shortness of breath • Can lead to pulmonary HTN
- 15. interstitiaL FiBrosis interstitiaL FiBrosis without granuLomatous without granuLomatous inFLammation inFLammation • Usually middle-aged men at time of diagnosis • Shortness of breath; may progress to cor pulmonale, hypoxia • Pneumoconioses – black lung disease – silicosis • most common chronic occupational disease – asbestosis • mesothelioma
- 16. interstitiaL FiBrosis with interstitiaL FiBrosis with granuLomatous granuLomatous inFLammation inFLammation • Sarcoidosis – cause unknown – affects many tissues but mostly lungs – present with shortness of breath, cough, chest pain, hemoptysis
- 17. PuLmonary eDema PuLmonary eDema • Fluid in alveoli • Increased BP in lung – normal is 25/8 mmHg with average at 15 mmHg • Microvascular injury – due to • toxic fumes • hot gases • septicemia • IV drug abuse • Main symptom is SOB
- 18. PuLmonary PuLmonary thromBoemBoLism thromBoemBoLism • About 50,000 deaths annually • Mostly from DVT • Inflammation predisposes you to it • Promoted by – CHF – pregnancy – birth control pills – prolonged bed rest – metastatic cancer – genetics • Most associated with no symptoms but some – cause lung infarcts – chest pain & dyspnea – death
- 19. PuLmonary PuLmonary hyPertension hyPertension • Sustained systolic pressure over 30 mmHg or average in excess of 25 mmHg • Vicious cycle • Most common cause is increased pulmonary vascular resistance • Usually secondary to – COPD – heart disease – collagen vascular diseases – recurrent pulmonary thromboemboli • With R heart failure is cor pulmonale • Thickening of arteriolar walls • SOB – chest pain – fatigue
- 20. aDuLt resPiratory aDuLt resPiratory Distress synDrome Distress synDrome • ARDS • Alveolar or pulmonary capillary damage • Pathogenesis – injury to endothelium or alveoli – neutrophils infiltrate – protein-rich fluid exudes into alveolar space – SOB occurs with rapid breathing which dries the fluid into a thick membrane – stiffens lungs – limits airflow & interferes with diffusion – hypoxia • 50% fatality • Causes – sepsis – smoke inhalation – near drowning – O2 toxicity – burns – DIC – fat embolism – endotoxic shock
- 21. Pneumonia Pneumonia • Inflammation of the lungs • Usually caused by bacteria • 80,000 deaths/yr • Alveolar pneumonia – usually acute – fill with inflammatory exudate – most common
- 22. • Bronchopneumonia – patchy inflammation – involves alveoli of more than 1 lobe – usually in basilar parts • Lobar pneumonia – consolidation of an entire lobe – almost always caused by S. pneumoniae
- 23. InterstItIal PneumonIa InterstItIal PneumonIa • Inflammation in septa • Diffuse & bilateral • Usually viral
- 24. • Etiology – mostly bacterial • S. pneumoniae • Haemophilus influenzae • Staph • E. coli • Pseudomonas • Pathogenesis – inhalation of droplets, aspiration of gastric contents, blood-borne spread – those susceptible include • immune deficiency • decreased cough reflex • impaired cilia • accumulated secretions • pulmonary congestion
- 25. • Community-acquired – acute pneumonia – bronchopneumonia – lobar pneumonia – Legionnaire’s disease – atypical pneumonia • Mycoplasma • Nosocomial – Commonly S. aureus & E.coli – Seen in • People with severe disease • Prolonged antibiotic therapy • People with internal mechanical devices • Aspiration – Inflammatory reaction due to corrosive effects – Those who are comatose or those with a stroke – Hi mortality rate
- 26. • Seen mostly in the young & the elderly • Hypoxia & death • Bacterial – high fever & chills – purulent sputum – increased neutrophils – cough – SOB • Interstitial – less severe – increased lymphocytes – cough – SOB
- 27. lung abscess lung abscess • Purulent inflammation with tissue necrosis & liquefaction • Usually have several types of bacteria with anaerobic • Most commonly due to aspiration of gastric contents • Foul-smelling sputum
- 28. tuberculosIs tuberculosIs • Mycobacterium tuberculosis • Chronic granulomatous inflammation with caseous necrosis
- 29. Pathogenesis
- 32. • Affects about 2 billion worldwide • Kills about 2 million/yr • 2nd only to AIDS • Associated with poverty, crowding, malnourishment, & chronic disease • PPD
- 33. • Low-grade fever • Night sweats • Malaise • Weight loss anorexia
- 34. Mycoses • Histoplasmosis • Coccidiomycosis • Cryptococcus
- 36. Lung neopLasms Lung neopLasms • Mostly due to metastasis • Bronchogenic carcinoma is the most common – most common of all cancers – #1 cancer death – about 90% are cigarette smokers
- 37. Bronchogenic Carcinoma Bronchogenic Carcinoma • Mostly caused by cigarettes – Direct relationship between incidence of cancer & number of cigarettes smoked – Direct relationship between precancerous changes in bronchial mucosa & number of cigarettes smoked
- 39. • Small cell carcinoma – 20% of cases – arise from specialized neuroendocrine cells of the bronchus – strongest relationship to cigarettes – aggressively malignant • Squamous cell carcinoma – 30% of cases – bronchial epithelium that has undergone metaplasia – arises centrally – most common in men who smoke – grows slower so better prognosis • Adenocarcinomas – 30% of cases – most well-differentiated – somewhat better prognosis – more peripheral in smaller bronchi – less associated with smoking • Large cell carcinoma – 15% of cases – poor prognosis – metastasizes early
- 40. Bronchial Carcinoid Tumor • 5% of lung cancers • Arise from bronchial neuroendocrine cells • Much less aggressive • Grows slow
- 41. pneumothorax pneumothorax • Air in pleural space • Causes atelectasis • May occur spontaneously • More frequent in people with emphysema who have large blebs near pleura • Traumatic penetration • Can be fatal • Tension pneumothorax – air in but not out
- 42. pLeuraL effusion pLeuraL effusion • Fluid in pleural space • Transudate from CHF most common • If blood, called hemothorax
- 43. pLeuritis • Inflammation • Pleurisy with each breath • Mostly caused by pneumonia